The present invention relates to systems and methods of monitoring a fluid and, more specifically, to systems and methods for cleaning optical windows used in an inline optical fluid analyzer.
In the oil and gas industry, it can be important to precisely know the characteristics and chemical composition of fluids circulating into and out of subterranean hydrocarbon-bearing formations. The analysis of such fluids can be conducted off-line using laboratory analyses, such as spectroscopic and/or wet chemical methods, which analyze an extracted sample of the fluid. Depending on the analysis required, however, such an approach can take hours to days to complete, and even in the best case scenario, a job will often be completed prior to the analysis being obtained. While such retrospective analyses can be satisfactory in certain cases, they nonetheless do not allow real-time or near real-time analysis capabilities.
Real-time monitoring of fluids can be of considerable interest in order to monitor how the fluids change over time, thereby providing an operator with a real time determination of the exact contents in a flow line or pipeline. For example, various adulterants and/or contaminants may be present within the fluids, such as waxes, paraffins, asphaltenes, water, etc. Such contaminants can lead to harmful scale formation, impurity buildup, and bacterial growth, all of which can impede processes in which the fluid is used, and even damage process equipment in certain cases. Know the particular contents of a fluid flow and their relative concentrations in real-time may allow an operator to proactively manage the fluid flow and maximize production capabilities.
In some applications, inline optical devices have been used to monitor a fluid in a flow line or pipeline in order to determine particular properties or characteristics of the fluid. Such optical devices are often equipped with sensor assemblies including an optical window through which measurements are made as a function of reflectance, transmittance, fluorescence, or another optical or photosensitive response. At least one difficulty encountered with inline optical devices is the fouling of the optical window, which limits the accuracy and testing capabilities of the optical device. One way to remove the film or residue built up on the optical window is to disassemble the optical device and physically clean or wipe the optical window. Such a process, however, can be quite time-consuming, and in aggressive fouling environments, this may require an excessive amount of disassembly and cleaning.